J. Bartnicki

Numerical Modeling of Cross — Wedge Rolling of Hollowed Shafts

In this article, the results of numerical calculations and experimental work of the cross‐wedge rolling (CWR) processes of hollowed shafts, realized with mandrels and without them, are presented. The results of numerical calculations for the CWR process of three rolls were also provided. On the basis of the calculations it was stated that the method of forming with the use of three rolls is the most appropriate for forming of hollowed shafts. This because in this process there is no excessive and irremovable ovalization of the normal cut, often observed in the process of rolling with two tools.

Numerical Analysis of Feed Rate Influence on Hollow Hub Shape during Rolling Extrusion Process

This paper presents the results of numerical calculations of rolling extrusion process of a hollow hub. Due to the necessity of flanges manufacturing at both sides of the product, in the analyzed process of rolling extrusion, as additional tool limiting axial metal flow a rear bumper was implemented [1,. Numerical calculations of the hub forming process were conducted basing on finite element method, applying software Deform3D v.X in conditions of three dimensional state of strain. The obtained small shape faults, in the form of characteristic triangulation and small changes of the hub walls thickness, show that it is possible to conduct the further research works of experimental character, with the application of modernized aggregate for the rolling extrusion process PO-2.

3D FEM analysis of basic process parameters in rotary piercing mill

In this paper the 3D FEM analysis of basic process parameters in rotary piercing mill is presented. In this process the material is formed by means of two skew rolls, two Diescher’s discs and a plug. The material is dragged by the rolls, it moves axially forward and rotates. The FEM analyze of the rotary piercing process was made under the conditions of 3D state of strain with taking into consideration the thermal phenomena. The calculations were made by means of commercial software MSC.SuperFORM2004 with application of different rolls’ skew angles, different plug designs and working positions. All the mentioned above variants were calculated at a different area reduction ratio. In the result, the progression of shapes, temperature and distributions of stress and strain in various sections of the analyzed tubes were characterized. The numerical results of calculations were justified during the stand test with the use of 100Cr6 steel. The comparisons of the numerical and experimental tests confirm good agreement between the obtained results.

Analysis of the extrusion process using a flexible tool

Przedstawiono wyniki prac dotyczących budowy modelu numerycznego procesu wytłaczania narzędziem elastycznym. W praktyce przemysłowej najczęściej spotyka się przekładki gumowe oraz elastomerowe, których zastosowanie wydatnie obniża koszty przygotowania narzędzi w porównaniu z tradycyjnymi, stalowymi tłocznikami. W artykule zaprezentowano rezultaty symulacji numerycznych zestawionych z procesem odkształcania narzędzia gumowego w specjalnie przygotowanym do tego przyrządzie modelowym. Wykorzystanie oprogramowania do modelowania numerycznego w połączeniu z przeprowadzeniem eksperymentu w warunkach laboratoryjnych pozwoliło na wstępne opracowanie modelu materiałowego do dalszych analiz procesów kształtowania narzędziami elastycznymi. SŁOWA KLUCZOWE: narzędzia elastyczne, MES

ANALYSIS OF RUBBER FORMING PROCESS OF FIRE BARRIER FROM TITANIUM CP2 ALLOY FOR AW 139 HELICOPTER

This paper presents conditions of forming products from titanium sheets by means of rubber stamping method. After introducing the issues connected with these elements manufacturing for aviation industry, considering standards and legal regulations, technological problems occurring during forming deep stiffening ribs. The results in the characteristic curvatures and distortion in the final products were generated in the process heterogeneous internal stress state. The Authors aimed at explaining and presenting of solutions limiting occurrence of chosen shape faults, which disqualify these products application in aviation industry. The proposed solutions significantly reduced the incidence of these unfavorable phenomena. The modified method of rub ber stamping of firewall from titanium alloy CP-2 sheet was successfully implement ed in manufacturing conditions of PZL Swidnik.

Numerical Analysis of Rolling Extrusion Process of a Toothed Shaft from Titanium Alloy Ti6Al4V

This paper presents results of numerical calculations of rolling extrusion process of a toothed shaft made from titanium alloy Ti6Al4V. FEM analysis was conducted applying the software DEFORM 3D for the process chosen technological parameters. The kinematics of metal flow in the area of the formed teeth was analyzed. Distributions of stresses, strains and temperatures during teeth forming were determined. Calculated values of axial and radial forces and moments acting on rotating roll tools allow for designing of tools for experimental verification of the designed forming process.

Theoretical analysis of rolling-extrusion process of axi-symmetrical parts

Rolling-extrusion process is potentially one of the new manufacturing technologies of stepped, hollowed parts. In this process material is formed by means of three rotational tools. The charge is provided by means of a pusher pushing the billet in a working space between the profiled rolls. Numerical research of this process in a few tools variants with the use of hollowed billets were made in order to determine the influence of tool shape geometry in this new forming method. In numerical simulations the MSC SuperForm2005 software was used. This software based on the finite element method and it allowed for analyzing of the influence of different geometrical and technological parameters on the course of the rolling-extrusion process. On the basis of calculations it was stated that the process stability depends on different shapes of profiled rolls and its rotary velocities correlated with pusher displacement. One of the phenomenon which disturbed the proper course of the hollowed parts manufacturing process was excessive ovalization of cross-sections of the formed workpiece. This disturbance was eliminated by the application of correctly combined tools velocities and reduction ratios. In this work the authors focused on determining the practical range of tools geometrical and kinematical parameters guaranteeing the proper course of the rolling-extrusion process of hollowed parts.